1. Field of the Invention
The present invention relates to an improved technology of an internal combustion engine with air-fuel mixture injection.
2. Description of Background Art
An air-fuel mixture injection type 2-cycle internal combustion engine in which compressed fuel from a fuel pump and pressurized air from an air-compressor to be supplied to a fuel injection valve are regulated in pressure by a differential pressure regulator, and excessive exhaust air which is run off by the differential pressure regulator when regulating the pressure is discharged into an air cleaner is known (for example, see Japanese Patent No. 2938992 (P.2-3, FIG. 1)). In addition, an air-fuel mixture injection type 2-cycle internal combustion engine in which an air-inlet port of the assist air compressor is connected to the clean side of the air cleaner is also known.
The work required to compress the air discharged as excessive air, which is a useless work in a sense, is performed by the compressor. In this sense, a drive force of the compressor corresponding to the compression of the excessive air is wasted, whereby fuel efficiency during driving of the internal combustion engine is lowered.
Therefore, it is desired to provide an improved technology in which improvement of fuel efficiency is achieved by regulating the amount of assist air adequately reducing the amount of excessive air supply, and eliminating the useless air compression work to improve driving efficiency of the air compressor, and in which air-intake noise of the air compressor by air-intake pulsation of the engine is reduced.